[Patch] shm cleanups

[Christoph Rohland <hans-christoph.rohland@sap.com>]

The following message was crippled somewhere on the way to linux-mm so
I resend it:
 
Hi Linus,

Here is a patch against 2.3.25 which

1) avoids vmalloc in the shm coding.
2) cleans a lot of cruft out of the shm headers
3) makes shm sysctl'able

I did test it a lot on SMP/HIGHMEM. Since 2.3.25 with and without this
breaks on swapping shm and other high memory load conditions I could
not verify everything. But I would like to see this in the mainstream
kernel. I will then proceed debugging the swapping issues.

Greetings
          Christoph

diff -uNr 2.3.25/arch/i386/kernel/sys_i386.c 2.3.25-shm3/arch/i386/kernel/sys_i386.c
--- 2.3.25/arch/i386/kernel/sys_i386.c	Fri Dec 18 01:27:35 1998
+++ 2.3.25-shm3/arch/i386/kernel/sys_i386.c	Wed Nov  3 11:28:11 1999
@@ -116,86 +116,71 @@
 	version = call >> 16; /* hack for backward compatibility */
 	call &= 0xffff;

-	if (call <= SEMCTL)
-		switch (call) {
-		case SEMOP:
-			return sys_semop (first, (struct sembuf *)ptr, second);
-		case SEMGET:
-			return sys_semget (first, second, third);
-		case SEMCTL: {
-			union semun fourth;
-			if (!ptr)
-				return -EINVAL;
-			if (get_user(fourth.__pad, (void **) ptr))
-				return -EFAULT;
-			return sys_semctl (first, second, third, fourth);
-			}
-		default:
-			return -EINVAL;
-		}
+        switch (call) {
+        case SEMOP:
+                return sys_semop (first, (struct sembuf *)ptr, second);
+        case SEMGET:
+                return sys_semget (first, second, third);
+        case SEMCTL: {
+                union semun fourth;
+                if (!ptr)
+                        return -EINVAL;
+                if (get_user(fourth.__pad, (void **) ptr))
+                        return -EFAULT;
+                return sys_semctl (first, second, third, fourth);
+        }

-	if (call <= MSGCTL) 
-		switch (call) {
-		case MSGSND:
-			return sys_msgsnd (first, (struct msgbuf *) ptr, 
-					  second, third);
-		case MSGRCV:
-			switch (version) {
-			case 0: {
-				struct ipc_kludge tmp;
-				if (!ptr)
-					return -EINVAL;
-				
-				if (copy_from_user(&tmp,
-						   (struct ipc_kludge *) ptr, 
-						   sizeof (tmp)))
-					return -EFAULT;
-				return sys_msgrcv (first, tmp.msgp, second,
-						   tmp.msgtyp, third);
-				}
-			default:
-				return sys_msgrcv (first,
-						   (struct msgbuf *) ptr,
-						   second, fifth, third);
-			}
-		case MSGGET:
-			return sys_msgget ((key_t) first, second);
-		case MSGCTL:
-			return sys_msgctl (first, second,
-					   (struct msqid_ds *) ptr);
-		default:
-			return -EINVAL;
-		}
-	if (call <= SHMCTL) 
-		switch (call) {
-		case SHMAT:
-			switch (version) {
-			default: {
-				ulong raddr;
-				ret = sys_shmat (first, (char *) ptr,
-						 second, &raddr);
-				if (ret)
-					return ret;
-				return put_user (raddr, (ulong *) third);
-			}
-			case 1:	/* iBCS2 emulator entry point */
-				if (!segment_eq(get_fs(), get_ds()))
-					return -EINVAL;
-				return sys_shmat (first, (char *) ptr,
-						  second, (ulong *) third);
-			}
-		case SHMDT: 
-			return sys_shmdt ((char *)ptr);
-		case SHMGET:
-			return sys_shmget (first, second, third);
-		case SHMCTL:
-			return sys_shmctl (first, second,
-					   (struct shmid_ds *) ptr);
-		default:
-			return -EINVAL;
-		}
-	
-	return -EINVAL;
+        case MSGSND:
+                return sys_msgsnd (first, (struct msgbuf *) ptr, 
+                                   second, third);
+        case MSGRCV:
+                switch (version) {
+                case 0: {
+                        struct ipc_kludge tmp;
+                        if (!ptr)
+                                return -EINVAL;
+                        
+                        if (copy_from_user(&tmp,
+                                           (struct ipc_kludge *) ptr, 
+                                           sizeof (tmp)))
+                                return -EFAULT;
+                        return sys_msgrcv (first, tmp.msgp, second,
+                                           tmp.msgtyp, third);
+                }
+                default:
+                        return sys_msgrcv (first,
+                                           (struct msgbuf *) ptr,
+                                           second, fifth, third);
+                }
+        case MSGGET:
+                return sys_msgget ((key_t) first, second);
+        case MSGCTL:
+                return sys_msgctl (first, second, (struct msqid_ds *) ptr);
+
+        case SHMAT:
+                switch (version) {
+                default: {
+                        ulong raddr;
+                        ret = sys_shmat (first, (char *) ptr, second, &raddr);
+                        if (ret)
+                                return ret;
+                        return put_user (raddr, (ulong *) third);
+                }
+                case 1:	/* iBCS2 emulator entry point */
+                        if (!segment_eq(get_fs(), get_ds()))
+                                return -EINVAL;
+                        return sys_shmat (first, (char *) ptr, second, (ulong *) third);
+                }
+        case SHMDT: 
+                return sys_shmdt ((char *)ptr);
+        case SHMGET:
+                return sys_shmget (first, second, third);
+        case SHMCTL:
+                return sys_shmctl (first, second,
+                                   (struct shmid_ds *) ptr);
+        default:
+                return -EINVAL;
+        }
 }

 /*
diff -uNr 2.3.25/include/asm-alpha/shmparam.h 2.3.25-shm3/include/asm-alpha/shmparam.h
--- 2.3.25/include/asm-alpha/shmparam.h	Mon Oct  7 14:12:29 1996
+++ 2.3.25-shm3/include/asm-alpha/shmparam.h	Wed Nov  3 11:28:11 1999
@@ -1,47 +1,6 @@
 #ifndef _ASMAXP_SHMPARAM_H
 #define _ASMAXP_SHMPARAM_H

-/*
- * Address range for shared memory attaches if no address passed to shmat().
- */
-#define SHM_RANGE_START	0x14000000000
-#define SHM_RANGE_END	0x15000000000
-
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the Alpha and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x3fa000			/* max shared seg size (bytes) */
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
-#define	SHMLBA PAGE_SIZE		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */
+#define	SHMLBA PAGE_SIZE		 /* attach addr a multiple of this */

 #endif /* _ASMAXP_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-arm/proc-armo/shmparam.h 2.3.25-shm3/include/asm-arm/proc-armo/shmparam.h
--- 2.3.25/include/asm-arm/proc-armo/shmparam.h	Wed Jan 21 01:39:42 1998
+++ 2.3.25-shm3/include/asm-arm/proc-armo/shmparam.h	Wed Nov  3 11:28:11 1999
@@ -9,9 +9,7 @@
 #ifndef __ASM_PROC_SHMPARAM_H
 #define __ASM_PROC_SHMPARAM_H

-#ifndef SHM_RANGE_START
-#define SHM_RANGE_START	0x00a00000
-#define SHM_RANGE_END	0x00c00000
+#ifndef SHMMAX
 #define SHMMAX		0x003fa000
 #endif

diff -uNr 2.3.25/include/asm-arm/proc-armv/shmparam.h 2.3.25-shm3/include/asm-arm/proc-armv/shmparam.h
--- 2.3.25/include/asm-arm/proc-armv/shmparam.h	Wed Jan 21 01:39:43 1998
+++ 2.3.25-shm3/include/asm-arm/proc-armv/shmparam.h	Wed Nov  3 11:28:11 1999
@@ -10,9 +10,7 @@
 #ifndef __ASM_PROC_SHMPARAM_H
 #define __ASM_PROC_SHMPARAM_H

-#ifndef SHM_RANGE_START
-#define SHM_RANGE_START	0x50000000
-#define SHM_RANGE_END	0x60000000
+#ifndef SHMMAX
 #define SHMMAX		0x01000000
 #endif

diff -uNr 2.3.25/include/asm-arm/shmparam.h 2.3.25-shm3/include/asm-arm/shmparam.h
--- 2.3.25/include/asm-arm/shmparam.h	Mon Oct 25 09:25:29 1999
+++ 2.3.25-shm3/include/asm-arm/shmparam.h	Wed Nov  3 11:28:11 1999
@@ -3,39 +3,6 @@

 #include <asm/proc/shmparam.h>

-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
-#define	SHMLBA PAGE_SIZE		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */
+#define	SHMLBA PAGE_SIZE		 /* attach addr a multiple of this */

 #endif /* _ASMARM_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-i386/shmparam.h 2.3.25-shm3/include/asm-i386/shmparam.h
--- 2.3.25/include/asm-i386/shmparam.h	Sun Nov  8 23:06:18 1998
+++ 2.3.25-shm3/include/asm-i386/shmparam.h	Wed Nov  3 11:28:11 1999
@@ -1,46 +1,6 @@
 #ifndef _ASMI386_SHMPARAM_H
 #define _ASMI386_SHMPARAM_H

-/* address range for shared memory attaches if no address passed to shmat() */
-#define SHM_RANGE_START	0x50000000
-#define SHM_RANGE_END	0x60000000
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x2000000		/* max shared seg size (bytes) */
-/* Try not to change the default shipped SHMMAX - people rely on it */
-
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
-#define	SHMLBA PAGE_SIZE		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */
+#define	SHMLBA PAGE_SIZE		 /* attach addr a multiple of this */

 #endif /* _ASMI386_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-m68k/shmparam.h 2.3.25-shm3/include/asm-m68k/shmparam.h
--- 2.3.25/include/asm-m68k/shmparam.h	Mon Oct 18 14:35:02 1999
+++ 2.3.25-shm3/include/asm-m68k/shmparam.h	Wed Nov  3 11:28:16 1999
@@ -1,49 +1,6 @@
 #ifndef _M68K_SHMPARAM_H
 #define _M68K_SHMPARAM_H

-/* address range for shared memory attaches if no address passed to shmat() */
-#ifndef CONFIG_SUN3
-#define SHM_RANGE_START	0xC0000000
-#define SHM_RANGE_END	0xD0000000
-#else
-#define SHM_RANGE_START	0x0C000000
-#define SHM_RANGE_END	0x0D000000
-#endif
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x1000000		/* max shared seg size (bytes) */
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
-#define	SHMLBA PAGE_SIZE		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */
+#define	SHMLBA PAGE_SIZE		 /* attach addr a multiple of this */

 #endif /* _M68K_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-mips/shmparam.h 2.3.25-shm3/include/asm-mips/shmparam.h
--- 2.3.25/include/asm-mips/shmparam.h	Sat Jun 26 02:37:53 1999
+++ 2.3.25-shm3/include/asm-mips/shmparam.h	Wed Nov  3 11:28:16 1999
@@ -1,49 +1,9 @@
 #ifndef __ASM_MIPS_SHMPARAM_H
 #define __ASM_MIPS_SHMPARAM_H

-/* address range for shared memory attaches if no address passed to shmat() */
-#define SHM_RANGE_START	0x50000000
-#define SHM_RANGE_END	0x60000000
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x2000000		/* max shared seg size (bytes) */
-/* Try not to change the default shipped SHMMAX - people rely on it */
-
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
 /*
  * This constant is very large but the ABI in it's wisdom says ...
  */
 #define	SHMLBA 0x40000			/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */

 #endif /* __ASM_MIPS_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-ppc/shmparam.h 2.3.25-shm3/include/asm-ppc/shmparam.h
--- 2.3.25/include/asm-ppc/shmparam.h	Mon Oct 18 14:35:24 1999
+++ 2.3.25-shm3/include/asm-ppc/shmparam.h	Wed Nov  3 11:28:16 1999
@@ -1,44 +1,6 @@
 #ifndef _PPC_SHMPARAM_H
 #define _PPC_SHMPARAM_H

-/* address range for shared memory attaches if no address passed to shmat() */
-#define SHM_RANGE_START	0x50000000
-#define SHM_RANGE_END	0x60000000
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x2000000		/* max shared seg size (bytes) */
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
-#define	SHMLBA PAGE_SIZE		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */
+#define	SHMLBA PAGE_SIZE		 /* attach addr a multiple of this */

 #endif /* _PPC_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-sh/shmparam.h 2.3.25-shm3/include/asm-sh/shmparam.h
--- 2.3.25/include/asm-sh/shmparam.h	Mon Oct 18 14:34:54 1999
+++ 2.3.25-shm3/include/asm-sh/shmparam.h	Wed Nov  3 11:28:16 1999
@@ -1,46 +1,6 @@
 #ifndef __ASM_SH_SHMPARAM_H
 #define __ASM_SH_SHMPARAM_H

-/* address range for shared memory attaches if no address passed to shmat() */
-#define SHM_RANGE_START	0x50000000
-#define SHM_RANGE_END	0x60000000
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x2000000		/* max shared seg size (bytes) */
-/* Try not to change the default shipped SHMMAX - people rely on it */
-
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
-#define	SHMLBA PAGE_SIZE		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */
+#define	SHMLBA PAGE_SIZE		 /* attach addr a multiple of this */

 #endif /* __ASM_SH_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-sparc/shmparam.h 2.3.25-shm3/include/asm-sparc/shmparam.h
--- 2.3.25/include/asm-sparc/shmparam.h	Sun Oct  4 19:22:44 1998
+++ 2.3.25-shm3/include/asm-sparc/shmparam.h	Wed Nov  3 11:28:16 1999
@@ -2,44 +2,6 @@
 #ifndef _ASMSPARC_SHMPARAM_H
 #define _ASMSPARC_SHMPARAM_H

-/* address range for shared memory attaches if no address passed to shmat() */
-#define SHM_RANGE_START	0x10000000
-#define SHM_RANGE_END	0x20000000
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x1000000		/* max shared seg size (bytes) */
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
-#define	SHMLBA PAGE_SIZE		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */
+#define	SHMLBA PAGE_SIZE		 /* attach addr a multiple of this */

 #endif /* _ASMSPARC_SHMPARAM_H */
diff -uNr 2.3.25/include/asm-sparc64/shmparam.h 2.3.25-shm3/include/asm-sparc64/shmparam.h
--- 2.3.25/include/asm-sparc64/shmparam.h	Sun Oct  4 19:22:44 1998
+++ 2.3.25-shm3/include/asm-sparc64/shmparam.h	Wed Nov  3 11:28:16 1999
@@ -2,46 +2,6 @@
 #ifndef _ASMSPARC64_SHMPARAM_H
 #define _ASMSPARC64_SHMPARAM_H

-/* XXX Redo most of this... */
-
-/* address range for shared memory attaches if no address passed to shmat() */
-#define SHM_RANGE_START	0x10000000
-#define SHM_RANGE_END	0x20000000
-
-/*
- * Format of a swap-entry for shared memory pages currently out in
- * swap space (see also mm/swap.c).
- *
- * SWP_TYPE = SHM_SWP_TYPE
- * SWP_OFFSET is used as follows:
- *
- *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
- *  bits 7..21: index of page within shared memory segment (SHM_IDX)
- *		(actually fewer bits get used since SHMMAX is so low)
- */
-
-/*
- * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
- * there is a static array of size SHMMNI.
- */
-#define _SHM_ID_BITS	7
-#define SHM_ID_MASK	((1<<_SHM_ID_BITS)-1)
-
-#define SHM_IDX_SHIFT	(_SHM_ID_BITS)
-#define _SHM_IDX_BITS	15
-#define SHM_IDX_MASK	((1<<_SHM_IDX_BITS)-1)
-
-/*
- * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
- * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
- */
-
-#define SHMMAX 0x1000000		/* max shared seg size (bytes) */
-#define SHMMIN 1 /* really PAGE_SIZE */	/* min shared seg size (bytes) */
-#define SHMMNI (1<<_SHM_ID_BITS)	/* max num of segs system wide */
-#define SHMALL				/* max shm system wide (pages) */ \
-	(1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
 #define	SHMLBA (PAGE_SIZE<<1)		/* attach addr a multiple of this */
-#define SHMSEG SHMMNI			/* max shared segs per process */

 #endif /* _ASMSPARC64_SHMPARAM_H */
diff -uNr 2.3.25/include/linux/shm.h 2.3.25-shm3/include/linux/shm.h
--- 2.3.25/include/linux/shm.h	Tue Nov  2 12:46:29 1999
+++ 2.3.25-shm3/include/linux/shm.h	Wed Nov  3 11:28:16 1999
@@ -3,6 +3,17 @@

 #include <linux/ipc.h>

+/*
+ * SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
+ * be increased by sysctl
+ */
+
+#define SHMMAX 0x2000000		 /* max shared seg size (bytes) */
+#define SHMMIN 1 /* really PAGE_SIZE */	 /* min shared seg size (bytes) */
+#define SHMMNI 128			 /* max num of segs system wide */
+#define SHMALL (SHMMAX/PAGE_SIZE*SHMMNI) /* max shm system wide (pages) */
+#define SHMSEG SHMMNI			 /* max shared segs per process */
+
 #include <asm/shmparam.h>

 struct shmid_ds {
@@ -17,15 +28,6 @@
 	unsigned short 		shm_unused;	/* compatibility */
 	void 			*shm_unused2;	/* ditto - used by DIPC */
 	void			*shm_unused3;	/* unused */
-};
-
-struct shmid_kernel
-{	
-	struct shmid_ds		u;
-	/* the following are private */
-	unsigned long		shm_npages;	/* size of segment (pages) */
-	pte_t			*shm_pages;	/* array of ptrs to frames -> SHMMAX */ 
-	struct vm_area_struct	*attaches;	/* descriptors for attaches */
 };

 /* permission flag for shmget */
diff -uNr 2.3.25/include/linux/swap.h 2.3.25-shm3/include/linux/swap.h
--- 2.3.25/include/linux/swap.h	Wed Nov  3 18:00:50 1999
+++ 2.3.25-shm3/include/linux/swap.h	Wed Nov  3 11:55:52 1999
@@ -122,17 +122,6 @@
 asmlinkage long sys_swapoff(const char *);
 asmlinkage long sys_swapon(const char *, int);

-/*
- * vm_ops not present page codes for shared memory.
- *
- * Will go away eventually..
- */
-#define SHM_SWP_TYPE 0x20
-
-/*
- * swap cache stuff (in linux/mm/swap_state.c)
- */
-
 #define SWAP_CACHE_INFO

 #ifdef SWAP_CACHE_INFO
diff -uNr 2.3.25/include/linux/sysctl.h 2.3.25-shm3/include/linux/sysctl.h
--- 2.3.25/include/linux/sysctl.h	Thu Oct 28 09:26:49 1999
+++ 2.3.25-shm3/include/linux/sysctl.h	Wed Nov  3 19:58:43 1999
@@ -103,8 +103,7 @@
 	KERN_MSGPOOL=37,        /* int: Maximum system message pool size */
 	KERN_SYSRQ=38,		/* int: Sysreq enable */
 	KERN_MAX_THREADS=39,    /* int: Maximum nr of threads in the system */
- 	KERN_RANDOM=40,		/* Random driver */
- 	KERN_SHMALL=41		/* int: Maximum size of shared memory */
+ 	KERN_RANDOM=40		/* Random driver */
 };

diff -uNr 2.3.25/ipc/shm.c 2.3.25-shm3/ipc/shm.c
--- 2.3.25/ipc/shm.c	Tue Nov  2 12:46:29 1999
+++ 2.3.25-shm3/ipc/shm.c	Wed Nov  3 11:55:39 1999
@@ -9,6 +9,8 @@
  * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
  * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
  * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
+ * avoid vmalloc and make shmmax, shmall, shmmni sysctl'able,
+ *                         Christoph Rohland <hans-christoph.rohland@sap.com>
  */

 #include <linux/config.h>
@@ -25,7 +27,17 @@
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>

-extern int ipcperms (struct ipc_perm *ipcp, short shmflg);
+#include "util.h"
+
+struct shmid_kernel /* extend struct shmis_ds with private fields */
+{	
+	struct shmid_ds		u;
+	unsigned long		shm_npages; /* size of segment (pages) */
+	pte_t			**shm_dir;  /* ptr to array of ptrs to frames -> SHMMAX */ 
+	struct vm_area_struct	*attaches;  /* descriptors for attaches */
+        int                     id; /* backreference to id for shm_close */
+};
+
 static int findkey (key_t key);
 static int newseg (key_t key, int shmflg, size_t size);
 static int shm_map (struct vm_area_struct *shmd);
@@ -38,13 +50,15 @@
 static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
 #endif

+unsigned int shm_prm[3] = {SHMMAX, SHMALL, SHMMNI};
+
 static int shm_tot = 0; /* total number of shared memory pages */
 static int shm_rss = 0; /* number of shared memory pages that are in memory */
 static int shm_swp = 0; /* number of shared memory pages that are in swap */
-static int max_shmid = 0; /* every used id is <= max_shmid */
+static int max_shmid = -1; /* every used id is <= max_shmid */
 static DECLARE_WAIT_QUEUE_HEAD(shm_wait); /* calling findkey() may need to wait */
-static struct shmid_kernel *shm_segs[SHMMNI];
-
+static struct shmid_kernel **shm_segs = NULL;
+static unsigned int num_segs = 0;
 static unsigned short shm_seq = 0; /* incremented, for recognizing stale ids */

 spinlock_t shm_lock = SPIN_LOCK_UNLOCKED;
@@ -56,22 +70,109 @@

 void __init shm_init (void)
 {
-	int id;
-
-	for (id = 0; id < SHMMNI; id++)
-		shm_segs[id] = (struct shmid_kernel *) IPC_UNUSED;
-	shm_tot = shm_rss = shm_seq = max_shmid = used_segs = 0;
-	init_waitqueue_head(&shm_wait);
 #ifdef CONFIG_PROC_FS
 	create_proc_read_entry("sysvipc/shm", 0, 0, sysvipc_shm_read_proc, NULL);
 #endif
 	return;
 }

+#define SHM_ENTRY(shp, index) (shp)->shm_dir[(index)/PTRS_PER_PTE][(index)%PTRS_PER_PTE]
+
+static pte_t **shm_alloc(unsigned long pages)
+{
+        unsigned short dir  = pages / PTRS_PER_PTE;
+        unsigned short last = pages % PTRS_PER_PTE;
+        pte_t **ret, **ptr;
+
+        ret = kmalloc ((dir+1) * sizeof(unsigned long), GFP_KERNEL);
+        if (ret == NULL)
+                return NULL;
+
+        for (ptr = ret; ptr < ret+dir ; ptr++)
+        {
+                *ptr = (pte_t *)__get_free_page (GFP_KERNEL);
+                if (*ptr == NULL)
+                        goto free;
+		memset (*ptr, 0, PAGE_SIZE); 
+        }
+
+        /* The last one is probably not of PAGE_SIZE: we use kmalloc */
+        if (last) {
+                *ptr = kmalloc (last*sizeof(pte_t *), GFP_KERNEL);
+                if (*ptr == NULL)
+                        goto free;
+		memset (*ptr, 0, last*sizeof(pte_t *));
+        }
+        
+        return ret;
+
+free:
+        /* The last failed: we decrement first */
+        while (--ptr >= ret)
+                free_page ((unsigned long)*ptr);
+
+        kfree (ret);
+        return NULL;
+}
+
+
+static void shm_free(pte_t** dir, unsigned long pages)
+{
+        pte_t **ptr = dir+pages/PTRS_PER_PTE;
+
+        /* first the last page */
+        if (pages%PTRS_PER_PTE)
+                kfree (*ptr);
+        /* now the whole pages */
+        while (--ptr >= dir)
+                free_page ((unsigned long)*ptr);
+
+        /* Now the indirect block */
+        kfree (dir);
+}
+
+static int shm_expand (unsigned int size)
+{
+        int id;
+        struct shmid_kernel ** new_array;
+
+        spin_unlock(&shm_lock);
+	new_array = kmalloc (size * sizeof(struct shmid_kernel *), GFP_KERNEL);
+        spin_lock(&shm_lock);
+
+	if (!new_array)
+                return -ENOMEM;
+
+        if (size <= num_segs){ /* We check this after kmalloc so
+                                   nobody changes num_segs afterwards */
+                /*
+                 * We never shrink the segment. If we shrink we have to
+                 * check for stale handles in newseg
+                 */
+                kfree (new_array);
+                return 0;
+        }
+
+        if (num_segs) {
+                memcpy (new_array, shm_segs,
+                        size*sizeof(struct shmid_kernel *));
+                kfree (shm_segs);
+        }
+        for (id = num_segs; id < size; id++) 
+		new_array[id] = (void *) IPC_UNUSED;
+
+        shm_segs = new_array;
+        num_segs = size;
+        return 0;
+}
+
 static int findkey (key_t key)
 {
 	int id;
 	struct shmid_kernel *shp;
+        
+        if (!num_segs)
+                return -1;

 	for (id = 0; id <= max_shmid; id++) {
 		if ((shp = shm_segs[id]) == IPC_NOID) {
@@ -89,9 +190,8 @@
 			__set_current_state(TASK_RUNNING);
 			remove_wait_queue(&shm_wait, &wait);
 		}
-		if (shp == IPC_UNUSED)
-			continue;
-		if (key == shp->u.shm_perm.key)
+		if (shp != IPC_UNUSED &&
+                    key == shp->u.shm_perm.key)
 			return id;
 	}
 	return -1;
@@ -99,18 +199,33 @@

 /*
  * allocate new shmid_kernel and pgtable. protected by shm_segs[id] = NOID.
+ * This has to be called with the shm_lock held
  */
 static int newseg (key_t key, int shmflg, size_t size)
 {
 	struct shmid_kernel *shp;
 	int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
-	int id;
+	int id, err;
+        unsigned int shmall, shmmni;

+        lock_kernel();
+        shmall = shm_prm[1];
+        shmmni = shm_prm[2];
+        if (shmmni > IPCMNI) {
+                printk ("shmmni reset to max of %u\n", IPCMNI);
+                shmmni = shm_prm[2] = IPCMNI;
+        }
+        unlock_kernel();
+
+        if (shmmni < used_segs)
+                return -ENOSPC;
+        if ((err = shm_expand (shmmni)))
+                return err;
 	if (size < SHMMIN)
 		return -EINVAL;
-	if (shm_tot + numpages >= SHMALL)
+	if (shm_tot + numpages >= shmall)
 		return -ENOSPC;
-	for (id = 0; id < SHMMNI; id++)
+	for (id = 0; id < num_segs; id++)
 		if (shm_segs[id] == IPC_UNUSED) {
 			shm_segs[id] = (struct shmid_kernel *) IPC_NOID;
 			goto found;
@@ -126,10 +241,8 @@
 		wake_up (&shm_wait);
 		return -ENOMEM;
 	}
-	lock_kernel();
-	shp->shm_pages = (pte_t *) vmalloc (numpages*sizeof(pte_t));
-	unlock_kernel();
-	if (!shp->shm_pages) {
+	shp->shm_dir = shm_alloc (numpages);
+	if (!shp->shm_dir) {
 		kfree(shp);
 		spin_lock(&shm_lock);
 		shm_segs[id] = (struct shmid_kernel *) IPC_UNUSED;
@@ -137,8 +250,6 @@
 		return -ENOMEM;
 	}

-	memset(shp->shm_pages, 0, numpages*sizeof(pte_t));
-
 	shp->u.shm_perm.key = key;
 	shp->u.shm_perm.mode = (shmflg & S_IRWXUGO);
 	shp->u.shm_perm.cuid = shp->u.shm_perm.uid = current->euid;
@@ -150,6 +261,7 @@
 	shp->u.shm_atime = shp->u.shm_dtime = 0;
 	shp->u.shm_ctime = CURRENT_TIME;
 	shp->shm_npages = numpages;
+        shp->id = id;

 	spin_lock(&shm_lock);

@@ -161,21 +273,25 @@
 	shm_segs[id] = shp;
 	used_segs++;
 	wake_up (&shm_wait);
-	return (unsigned int) shp->u.shm_perm.seq * SHMMNI + id;
+	return (unsigned int) shp->u.shm_perm.seq * IPCMNI + id;
 }

-size_t shmmax = SHMMAX;
-
 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 {
 	struct shmid_kernel *shp;
 	int err, id = 0;
+        size_t shmmax;
+
+        lock_kernel();
+        shmmax = shm_prm[0];
+        unlock_kernel();
+
+	if (size > shmmax)
+		return -EINVAL;

 	down(&current->mm->mmap_sem);
 	spin_lock(&shm_lock);
-	if (size > shmmax) {
-		err = -EINVAL;
-	} else if (key == IPC_PRIVATE) {
+	if (key == IPC_PRIVATE) {
 		err = newseg(key, shmflg, size);
 	} else if ((id = findkey (key)) == -1) {
 		if (!(shmflg & IPC_CREAT))
@@ -193,7 +309,7 @@
 		else if (ipcperms (&shp->u.shm_perm, shmflg))
 			err = -EACCES;
 		else
-			err = (int) shp->u.shm_perm.seq * SHMMNI + id;
+			err = (int) shp->u.shm_perm.seq * IPCMNI + id;
 	}
 	spin_unlock(&shm_lock);
 	up(&current->mm->mmap_sem);
@@ -214,18 +330,18 @@
 	if (shp == IPC_NOID || shp == IPC_UNUSED)
 		BUG();
 	shp->u.shm_perm.seq++;     /* for shmat */
-	shm_seq = (shm_seq+1) % ((unsigned)(1<<31)/SHMMNI); /* increment, but avoid overflow */
+	shm_seq = (shm_seq+1) % ((unsigned)(1<<31)/IPCMNI); /* increment, but avoid overflow */
 	shm_segs[id] = (struct shmid_kernel *) IPC_UNUSED;
 	used_segs--;
 	if (id == max_shmid)
-		while (max_shmid && (shm_segs[--max_shmid] == IPC_UNUSED));
-	if (!shp->shm_pages)
-		BUG();
+		while (max_shmid-- > 0 && (shm_segs[max_shmid] == IPC_UNUSED));
+	if (!shp->shm_dir)
+                BUG();
 	spin_unlock(&shm_lock);
 	numpages = shp->shm_npages;
 	for (i = 0, rss = 0, swp = 0; i < numpages ; i++) {
 		pte_t pte;
-		pte = shp->shm_pages[i];
+		pte = SHM_ENTRY (shp,i);
 		if (pte_none(pte))
 			continue;
 		if (pte_present(pte)) {
@@ -238,9 +354,7 @@
 			swp++;
 		}
 	}
-	lock_kernel();
-	vfree(shp->shm_pages);
-	unlock_kernel();
+	shm_free (shp->shm_dir, numpages);
 	kfree(shp);
 	spin_lock(&shm_lock);
 	shm_rss -= rss;
@@ -269,19 +383,20 @@
 	case IPC_INFO:
 	{
 		struct shminfo shminfo;
+		spin_unlock(&shm_lock);
 		err = -EFAULT;
 		if (!buf)
 			goto out;
-		shminfo.shmmni = SHMMNI;
-		shminfo.shmmax = shmmax;
+                lock_kernel();
+		shminfo.shmmni = shminfo.shmseg = shm_prm[2];
+		shminfo.shmmax = shm_prm[0];
+		shminfo.shmall = shm_prm[1];
+                unlock_kernel();
 		shminfo.shmmin = SHMMIN;
-		shminfo.shmall = SHMALL;
-		shminfo.shmseg = SHMSEG;
-		spin_unlock(&shm_lock);
 		if(copy_to_user (buf, &shminfo, sizeof(struct shminfo)))
 			goto out_unlocked;
 		spin_lock(&shm_lock);
-		err = max_shmid;
+		err = max_shmid < 0 ? 0 : max_shmid;
 		goto out;
 	}
 	case SHM_INFO:
@@ -298,7 +413,7 @@
 		if(copy_to_user (buf, &shm_info, sizeof(shm_info)))
 			goto out_unlocked;
 		spin_lock(&shm_lock);
-		err = max_shmid;
+		err = max_shmid < 0 ? 0 : max_shmid;
 		goto out;
 	}
 	case SHM_STAT:
@@ -310,7 +425,7 @@
 			goto out;
 		if (ipcperms (&shp->u.shm_perm, S_IRUGO))
 			goto out;
-		id = (unsigned int) shp->u.shm_perm.seq * SHMMNI + shmid;
+		id = (unsigned int) shp->u.shm_perm.seq * IPCMNI + shmid;
 		err = -EFAULT;
 		spin_unlock(&shm_lock);
 		if(copy_to_user (buf, &shp->u, sizeof(*buf)))
@@ -320,12 +435,13 @@
 		goto out;
 	}

-	shp = shm_segs[id = (unsigned int) shmid % SHMMNI];
 	err = -EINVAL;
-	if (shp == IPC_UNUSED || shp == IPC_NOID)
+	if ((id = (unsigned int) shmid % IPCMNI) > max_shmid)
+		goto out;
+	if ((shp = shm_segs[id]) == IPC_UNUSED || shp == IPC_NOID)
 		goto out;
 	err = -EIDRM;
-	if (shp->u.shm_perm.seq != (unsigned int) shmid / SHMMNI)
+	if (shp->u.shm_perm.seq != (unsigned int) shmid / IPCMNI)
 		goto out;
 	ipcp = &shp->u.shm_perm;

@@ -480,7 +596,7 @@
 	if (shmid < 0)
 		goto out;

-	shp = shm_segs[id = (unsigned int) shmid % SHMMNI];
+	shp = shm_segs[id = (unsigned int) shmid % IPCMNI];
 	if (shp == IPC_UNUSED || shp == IPC_NOID)
 		goto out;

@@ -523,7 +639,7 @@
 	if (ipcperms(&shp->u.shm_perm, shmflg & SHM_RDONLY ? S_IRUGO : S_IRUGO|S_IWUGO))
 		goto out;
 	err = -EIDRM;
-	if (shp->u.shm_perm.seq != (unsigned int) shmid / SHMMNI)
+	if (shp->u.shm_perm.seq != (unsigned int) shmid / IPCMNI)
 		goto out;

 	spin_unlock(&shm_lock);
@@ -532,13 +648,13 @@
 	spin_lock(&shm_lock);
 	if (!shmd)
 		goto out;
-	if ((shp != shm_segs[id]) || (shp->u.shm_perm.seq != (unsigned int) shmid / SHMMNI)) {
+	if ((shp != shm_segs[id]) || (shp->u.shm_perm.seq != (unsigned int) shmid / IPCMNI)) {
 		kmem_cache_free(vm_area_cachep, shmd);
 		err = -EIDRM;
 		goto out;
 	}

-	shmd->vm_private_data = shm_segs + id;
+	shmd->vm_private_data = shm_segs[id];
 	shmd->vm_start = addr;
 	shmd->vm_end = addr + shp->shm_npages * PAGE_SIZE;
 	shmd->vm_mm = current->mm;
@@ -584,7 +700,7 @@
 	struct shmid_kernel *shp;

 	spin_lock(&shm_lock);
-	shp = *(struct shmid_kernel **) shmd->vm_private_data;
+	shp = (struct shmid_kernel *) shmd->vm_private_data;
 	insert_attach(shp,shmd);  /* insert shmd into shp->attaches */
 	shp->u.shm_nattch++;
 	shp->u.shm_atime = CURRENT_TIME;
@@ -604,14 +720,12 @@

 	spin_lock(&shm_lock);
 	/* remove from the list of attaches of the shm segment */
-	shp = *(struct shmid_kernel **) shmd->vm_private_data;
+	shp = (struct shmid_kernel *) shmd->vm_private_data;
 	remove_attach(shp,shmd);  /* remove from shp->attaches */
   	shp->u.shm_lpid = current->pid;
 	shp->u.shm_dtime = CURRENT_TIME;
-	if (--shp->u.shm_nattch <= 0 && shp->u.shm_perm.mode & SHM_DEST) {
-		unsigned int id = (struct shmid_kernel **)shmd->vm_private_data - shm_segs;
-		killseg (id);
-	}
+	if (--shp->u.shm_nattch <= 0 && shp->u.shm_perm.mode & SHM_DEST)
+		killseg (shp->id);
 	spin_unlock(&shm_lock);
 }

@@ -648,7 +762,7 @@
 }

 /*
- * page not present ... go through shm_pages
+ * page not present ... go through shm_dir
  */
 static struct page * shm_nopage(struct vm_area_struct * shmd, unsigned long address, int no_share)
 {
@@ -657,13 +771,13 @@
 	unsigned int idx;
 	struct page * page;

-	shp = *(struct shmid_kernel **) shmd->vm_private_data;
+	shp = (struct shmid_kernel *) shmd->vm_private_data;
 	idx = (address - shmd->vm_start) >> PAGE_SHIFT;
 	idx += shmd->vm_pgoff;

 	spin_lock(&shm_lock);
 again:
-	pte = shp->shm_pages[idx];
+	pte = SHM_ENTRY(shp,idx);
 	if (!pte_present(pte)) {
 		if (pte_none(pte)) {
 			spin_unlock(&shm_lock);
@@ -672,7 +786,7 @@
 				goto oom;
 			clear_highpage(page);
 			spin_lock(&shm_lock);
-			if (pte_val(pte) != pte_val(shp->shm_pages[idx]))
+			if (pte_val(pte) != pte_val(SHM_ENTRY(shp, idx)))
 				goto changed;
 		} else {
 			swp_entry_t entry = pte_to_swp_entry(pte);
@@ -694,18 +808,18 @@
 			unlock_kernel();
 			spin_lock(&shm_lock);
 			shm_swp--;
-			pte = shp->shm_pages[idx];
+			pte = SHM_ENTRY(shp, idx);
 			if (pte_present(pte))
 				goto present;
 		}
 		shm_rss++;
 		pte = pte_mkdirty(mk_pte(page, PAGE_SHARED));
-		shp->shm_pages[idx] = pte;
+		SHM_ENTRY(shp, idx) = pte;
 	} else
 		--current->maj_flt;  /* was incremented in do_no_page */

 done:
-	/* pte_val(pte) == shp->shm_pages[idx] */
+	/* pte_val(pte) == SHM_ENTRY (shp, idx) */
 	get_page(pte_page(pte));
 	spin_unlock(&shm_lock);
 	current->min_flt++;
@@ -770,7 +884,7 @@
 	if (idx >= shp->shm_npages)
 		goto next_id;

-	page = shp->shm_pages[idx];
+	page = SHM_ENTRY(shp, idx);
 	if (!pte_present(page))
 		goto check_table;
 	page_map = pte_page(page);
@@ -792,7 +906,7 @@
 		goto check_table;
 	if (!(page_map = prepare_highmem_swapout(page_map)))
 		goto check_table;
-	shp->shm_pages[idx] = swp_entry_to_pte(swap_entry);
+	SHM_ENTRY (shp, idx) = swp_entry_to_pte(swap_entry);
 	swap_successes++;
 	shm_swp++;
 	shm_rss--;
@@ -812,12 +926,12 @@
  * Free the swap entry and set the new pte for the shm page.
  */
 static void shm_unuse_page(struct shmid_kernel *shp, unsigned long idx,
-			swp_entry_t entry, struct page *page)
+			   swp_entry_t entry, struct page *page)
 {
 	pte_t pte;

 	pte = pte_mkdirty(mk_pte(page, PAGE_SHARED));
-	shp->shm_pages[idx] = pte;
+	SHM_ENTRY(shp, idx) = pte;
 	get_page(page);
 	shm_rss++;

@@ -837,16 +951,16 @@
 	int i, n;

 	spin_lock(&shm_lock);
-	for (i = 0; i < SHMMNI; i++) {
+	for (i = 0; i <= max_shmid; i++) {
 		struct shmid_kernel *seg = shm_segs[i];
 		if ((seg == IPC_UNUSED) || (seg == IPC_NOID))
 			continue;
 		for (n = 0; n < seg->shm_npages; n++) {
-			if (pte_none(seg->shm_pages[n]))
+			if (pte_none(SHM_ENTRY(seg,n)))
 				continue;
-			if (pte_present(seg->shm_pages[n]))
+			if (pte_present(SHM_ENTRY(seg,n)))
 				continue;
-			if (pte_to_swp_entry(seg->shm_pages[n]).val == entry.val) {
+			if (pte_to_swp_entry(SHM_ENTRY(seg,n)).val == entry.val) {
 				shm_unuse_page(seg, n, entry, page);
 				return;
 			}
@@ -865,7 +979,7 @@
     	len += sprintf(buffer, "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n");

 	spin_lock(&shm_lock);
-    	for(i = 0; i < SHMMNI; i++)
+    	for(i = 0; i <= max_shmid; i++)
 		if(shm_segs[i] != IPC_UNUSED) {
 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
@@ -877,7 +991,7 @@
 				format = BIG_STRING;
 	    		len += sprintf(buffer + len, format,
 			shm_segs[i]->u.shm_perm.key,
-			shm_segs[i]->u.shm_perm.seq * SHMMNI + i,
+			shm_segs[i]->u.shm_perm.seq * IPCMNI + i,
 			shm_segs[i]->u.shm_perm.mode,
 			shm_segs[i]->u.shm_segsz,
 			shm_segs[i]->u.shm_cpid,
diff -uNr 2.3.25/ipc/util.c 2.3.25-shm3/ipc/util.c
--- 2.3.25/ipc/util.c	Tue Nov  2 12:46:29 1999
+++ 2.3.25-shm3/ipc/util.c	Wed Nov  3 20:04:41 1999
@@ -14,6 +14,8 @@
 #include <linux/init.h>
 #include <linux/msg.h>

+#include "util.h"
+
 #if defined(CONFIG_SYSVIPC)

 extern void sem_init (void), msg_init (void), shm_init (void);
diff -uNr 2.3.25/ipc/util.h 2.3.25-shm3/ipc/util.h
--- 2.3.25/ipc/util.h	Thu Jan  1 01:00:00 1970
+++ 2.3.25-shm3/ipc/util.h	Wed Nov  3 11:28:16 1999
@@ -0,0 +1,12 @@
+/*
+ * linux/ipc/util.h
+ * Copyright (C) 1999 Christoph Rohland
+ */
+
+/*
+ * IPCMNI is the absolute maximum for ipc identifier. This is used to
+ * detect stale identifiers
+ */
+#define IPCMNI (1<<15)          
+
+extern int ipcperms (struct ipc_perm *ipcp, short shmflg);
diff -uNr 2.3.25/kernel/sysctl.c 2.3.25-shm3/kernel/sysctl.c
--- 2.3.25/kernel/sysctl.c	Tue Nov  2 12:46:29 1999
+++ 2.3.25-shm3/kernel/sysctl.c	Wed Nov  3 11:32:02 1999
@@ -49,7 +49,7 @@
 extern int sg_big_buff;
 #endif
 #ifdef CONFIG_SYSVIPC
-extern size_t shmmax;
+extern size_t shm_prm[];
 #endif

 #ifdef __sparc__
@@ -213,7 +213,7 @@
 	{KERN_RTSIGMAX, "rtsig-max", &max_queued_signals, sizeof(int),
 	 0644, NULL, &proc_dointvec},
 #ifdef CONFIG_SYSVIPC
-	{KERN_SHMMAX, "shmmax", &shmmax, sizeof (size_t),
+	{KERN_SHMMAX, "shmmax", &shm_prm, 3*sizeof (size_t),
 	 0644, NULL, &proc_doulongvec_minmax},
 #endif
 #ifdef CONFIG_MAGIC_SYSRQ
diff -uNr 2.3.25/mm/swap_state.c 2.3.25-shm3/mm/swap_state.c
--- 2.3.25/mm/swap_state.c	Tue Nov  2 12:46:29 1999
+++ 2.3.25-shm3/mm/swap_state.c	Wed Nov  3 11:28:16 1999
@@ -68,8 +68,6 @@
 	if (!entry.val)
 		goto out;
 	type = SWP_TYPE(entry);
-	if (type & SHM_SWP_TYPE)
-		goto out;
 	if (type >= nr_swapfiles)
 		goto bad_file;
 	p = type + swap_info;
@@ -115,8 +113,6 @@
 	if (!entry.val)
 		goto bad_entry;
 	type = SWP_TYPE(entry);
-	if (type & SHM_SWP_TYPE)
-		goto out;
 	if (type >= nr_swapfiles)
 		goto bad_file;
 	p = type + swap_info;
diff -uNr 2.3.25/mm/swapfile.c 2.3.25-shm3/mm/swapfile.c
--- 2.3.25/mm/swapfile.c	Tue Nov  2 12:46:29 1999
+++ 2.3.25-shm3/mm/swapfile.c	Wed Nov  3 11:28:16 1999
@@ -135,8 +135,6 @@
 		goto out;

 	type = SWP_TYPE(entry);
-	if (type & SHM_SWP_TYPE)
-		goto out;
 	if (type >= nr_swapfiles)
 		goto bad_nofile;
 	p = & swap_info[type];
@@ -190,8 +188,6 @@
 		goto new_swap_entry;
 	entry.val = page->index;
 	type = SWP_TYPE(entry);
-	if (type & SHM_SWP_TYPE)
-		goto new_swap_entry;
 	if (type >= nr_swapfiles)
 		goto new_swap_entry;
 	p = type + swap_info;
--
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